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Home >> Cadillac >> 2004 >> CTS Base, 3.6 7 >> Repair and Diagnosis >> External Pages >> Different variant/trim >> Section 8 (Engine Mechanical - 5.7L (LS6)) >> Repair Instructions >> Off-Vehicle Repair Instructions >> Crankshaft and Bearings Cleaning and Inspection >> Measuring Main Bearing Clearance - Gaging Plastic Method

Measuring Main Bearing Clearance - Gaging Plastic Method

WARNING: This page is about a different variant/trim than selected.
    IMPORTANT:
    • The crankshaft main bearings are a precision insert type. Main bearing caps are machined with the engine block, for proper clearance, and cannot be shimmed or filed for bearing fit. If the clearances are found to be excessive, new bearings and/or engine block and cap repair or replacement may be required.
    • Do not rotate the crankshaft while gaging plastic is between the crankshaft journal and the bearing surface.
    • The crankshaft bearing clearances are critical. Excessive bearing clearance may effect crankshaft position sensor signals and may effect On-Board Diagnostics (OBD) II system operation.
    • Remove the bearing cap side bolts prior to cap removal.
    Fig 1: View Of Bearing Cap Bolts & Studs
    GM156155Courtesy of GENERAL MOTORS CORP.
  1. Remove the bearing cap M8 bolts.
    2. Fig 2: View Of Crankshaft Main Bearing Caps
    GM156152Courtesy of GENERAL MOTORS CORP.
  2. Remove the bearing cap M10 bolts and studs.
    3. NOTE: Refer to Fastener Notice in Cautions and Notices.
    Fig 3: View Of J 6125-1B & J 41818 Removing Main Bearing Cap
    GM63188Courtesy of GENERAL MOTORS CORP.
  3. Install the J 41818  to the bearing cap.

    Tighten:  Tighten the J 41818  bolts to 11 N.m (100 lb in).

  4. Install the J 6125-1B  to the. See Special Tools and Equipment .J 41818  in order to remove the bearing cap.
    5. Fig 4: View Of Crankshaft Bearings & Bearing Caps
    GM64293Courtesy of GENERAL MOTORS CORP.
  5. Remove the bearing cap and lower bearing.
    6. Fig 5: View Of Gaging Plastic Installed On Crankshaft Journal
    GM4980Courtesy of GENERAL MOTORS CORP.
  6. Install gaging plastic onto the crankshaft journal. Install the gaging plastic the full width of crankshaft bearing journal.
    7. Fig 6: Crankshaft Main Bearing Cap Bolt Tightening Sequence
    GM63214Courtesy of GENERAL MOTORS CORP.
  7. Install the bearing, bearing cap, bolts and studs.

    Tighten: 

    1. Tighten the M10 bolts (1-10) a first pass in sequence to 20 N.m (15 lb ft).
    2. Tighten the M10 bolts (1-10) a final pass in sequence to 80 degrees using the J 45059  .
    3. Tighten the M10 studs (11-20) a first pass in sequence to 20 N.m (15 lb ft).
    4. Tighten the M10 studs (11-20) a final pass in sequence to 53 degrees using the J 45059  .
    5. Tighten the M8 bolts to 25 N.m (18 lb ft).

      Tighten the bolt on one side of the bearing cap and then tighten the bolt on the opposite side of the same bearing cap.

    8. Fig 7: View Of Bearing Cap Bolts & Studs
    GM156155Courtesy of GENERAL MOTORS CORP.
    IMPORTANT: Remove the bearing cap side bolts prior to cap removal.
  8. Remove the bearing cap M8 bolts.
    9. Fig 8: View Of Crankshaft Main Bearing Caps
    GM156152Courtesy of GENERAL MOTORS CORP.
  9. Remove the bearing cap M10 bolts and studs.
    10. Fig 9: View Of J 6125-1B & J 41818 Removing Main Bearing Cap
    GM63188Courtesy of GENERAL MOTORS CORP.
  10. Use the J 41818  and the J 6125-1B  in order to remove the bearing cap. See Special Tools and Equipment .
    11. Fig 10: Measuring Gaging Plastic
    GM4981Courtesy of GENERAL MOTORS CORP.
  11. Measure the gaging plastic at its widest area using the scale supplied with the plastic gaging kit.
    • If the gaging plastic shows irregularity in the journal exceeding 0.025 mm (0.001 in), remove the crankshaft and measure the journal with a micrometer.
    • If the bearing clearance is greater than 0.065 mm (0.0025 in), select and install an undersized bearing set, and measure the clearance with gaging plastic.
    • If clearance cannot be brought to specifications, replace the crankshaft or grind the crankshaft for use with the next undersized bearing.
    12. Fig 11: Measuring Crankshaft End Play
    GM64316Courtesy of GENERAL MOTORS CORP.
  12. Measure the crankshaft end play.
    1. Thrust the crankshaft forward or rearward.
    2. Insert a feeler gage between the center crankshaft bearing and the bearing surface of the crankshaft and measure the bearing clearance. Refer to Engine Mechanical Specifications (LS6) .
    3. If the bearing clearance is not within specifications:
      • Inspect the thrust surfaces for nicks, gouges or raised metal. Minor imperfections may be removed with a fine stone.
      • Replace the thrust bearings and measure the end play.
      • If the correct measurements cannot be obtained, repair the crankshaft thrust surfaces or replace the crankshaft.
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